Push switch



Oct. 18, 1932. H. c. HANSEN ET AL PUSH SWITCH Filed May 5, 1931INVENTORS HANS CHRISTIAN HANSEN ALFRED JOHN BENNETT yel'afZ-Zarny'Patented oet. 1s, 1932 UNITED `STATES PATENT OFFICE HANS CHRISTIANHANSEN, OF WEST HARTFORD, AND ALFRED JOHN-BENNETT, F

HARTFORD, CONNECTICUT, ASSIGNORS TO THE ARROW-HART & HEGEMAN ELEC- TRICCOMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT PUSHSWITCH Application. mea my 5, 1931. serial No. 535,224,

This invention relates to switches which are adapted to be operated bypressure -applied to a spring pressed plunger. More articularly theinvention relates to a swltch 6 which is normally biased in'one positionbut which upon application of pressure snaps to another position andupon removal of that pressure returns to its original position.

The switch is particularly useful in control- 10 ling lighting circuitsfor illuminating closets,

iceboxes and the'like wherein it is desired to illuminate the interiorupon o ening of the door and to extinguish the light y closing the door.However, the switch is not limited to .15 such use, but is applicable touse in many other situations.

It often happens in mounting switches of the above type that slightinaccuracies creep in whichwould permit-the door to impart 20 greatermovement than necessary to the switch operating member. Unless provisionis made to take care of inaccuracies in mounting and expansion andcontraction of the members adj acent'the switch and upon which 25 it ismounted, the switch may become permanently damaged by excessive movementof the switch operating member.

Therefore, it is an object of this invention to provide a switch of theabove type with 3 means to take up any excess movement of the door orother devicefor switch actuation, so that the switch mechanism will notbe damaged by such excess movement.

Another object of .the invention is to pro vide a compact easilymanufactured'substa-ntially built switch of the above type. Otherobjects and advantages of the invention will appear as it is describedin connection with the accompanying drawing. In the draw- 1ng:-

Fig. 1 is an elevation view of the invention with the operatingmechanism shown in midsection and the switch contacts in closed circuitposition.

5 Fig. 2 is a view similar to Fig. 1 but with the switch in open circuitposition.

Fig. 3 is a view similar to Fig. 1 but showing the switch parts in theposition taken by them when they are given an excess movem ment by thedoor or other actuating device.

Fig. 4 is a sectional elevation view of the invention with the sectiontaken on the line 4-4 of Fig. 1.

Fig. 5 is a detail view of the plunger.

Referring to the drawing the switch proper is of the type shown in theGuett Patent 1,511,809 patented October 14, 1924, in which a laminatedinsulating base contains suitable contacts 12 which are adapted to bebridged by an anti-friction roller 14 which moves in a switch cavity 15in the insulating base. rThis roller is moved by a switching member 16,through the agency of a switch operating lever 18 as will hereinafter bemore fully described. A metallic casing 2O embraces the insulating baseand together with the rivets 22 confines the laminations of the base;There is an opening in the top of the metallic casing in which issecured an eX- ternally threaded sleeve 24 for mounting the switch inthe desired location.

A hollow cylindrical plunger 26 is slidably received within the sleeve24. This plunger has a.pair of diametrically opposed slots 27 formed inits lower end through which projects a spindle 28 mounted diametricallyin the sleevek 24 and upon which is a pivotally mounted switch operatingbell crank lever 18. One arm 18a of this lever engages in an aperture 29in the bottom` part of the plunger,l thisaperture 29 being spaced midwayaround the plunger between the slots 27. The other arm 185 of the bellcrank lever 18 `engages with the switching member 16 to cause movement.thereof in the manner described in the Guett Patent 1,511,809.

From the foregoing it will be apparent that if the plunger is moved upand down within the mounting sleeve'the arm 18a will be caused to rotateabout the spindle 28 and hence will cause the arm 18?) to move and throwthe switching member 16 from oil to on position and vice versa.

.The range of movement of the bell crank operating lever 18 iscontrolled by the following means.

The upward movement of the plunger is limited by the lower end of theslots 27 abutting the spindle 28 and also by arm 18?) abutting theinside of the sleeve 24. The 100 downward movement of the plunger islimited by the upper end of the slots 27 abutting the spindle and alsoby a shoulder 30 on the upper end of the plunger 26 abutting the top ofthe sleeve 24.

In order to prevent the spindle 28 from being deformed and also toprotect the whole switch against injury by reason of excess pressurebeing put upon the plunger 26, we provide the following mechanism. Anauxiliary coil spring 34 is placed within the plunger 26 with its lowerend resting upon an inwardly directed shoulder 32 formed midway down theinside of the plunger. The upper end of this coil spring presses againsta button 36 which is located in top of the plunger and is movablerelative thereto. The lower part 36a of this button is enlarged and isof substantially the same diameter as the inside of the plunger.

In assembling the operating mechanism, the button 36 is placed withinthe plunger 24 with the auxiliary coil spring 34 under tension. Then theupper end of the plunger is turned over the enlarged lowerportion 36a ofthebutton, thus sealing the button within the plunger with its smallupper end 36?) projecting beyond the end of the: plunger.

It is desirable that the switch should be at all times biased to closedcircuit position. For this purpose we provide a main coil spring 38 ofless strength than the auxiliary spring 34 and having a smaller diameterthan the auxiliary spring and working within the auxiliary spring. It isessential that both of these springs be of greater strength than theswitch spring 168 as will hereinafter appear. The upper end of this mainspring presses against the enlarged bottom of the button 36 while thelower end of the spring fits into a cylindrical cup 40 located in thebottom of the plunger, the diameter of the cup being approximately thesame as the inside diameter oflthe lower end of the plunger. The bottomof the cup rests on the spindle 28 and therefore the cup is held againstdownward movement relative to the sleeve 24 as the main spring 38 iscompressed when the plunger is depressed. In order thatthe bell cranklever may move freely a slot 42 is cut`in the bottom of the cup topermit the bell crank lever to rotate without engaging the bottomsurface of the cup. However, this slot 42 serves to hold the bell Icrank lever from axial movement along the spindle.

The operation of the device will now be described. llVhen` the switch isassembled the parts assume the position shown in Fig. 1. In this ligurethe main spring pressing the cup 40 againstthe spindle 28v and pressingthe button 36 against the overturned top of the plunger, causestheplunger 24 to take its uppermost position. This causes the arm 186 ofthe switch operating lever 18 to take itsleft hand position. See Fig. 1.Now when pressure is exerted upon the button, the pressure istransmitted through the auxiliary spring to the plunger which is causedto de-v scend by reason of the strength of the auxiliary spring beinggreater than that of the spring of the switch mechanism. Depression ofthe plunger causes the bell crank lever 18l to rotate the arm 18?) ofthe lever eventually causing the switching member 16 to move to opencircuit position as shown in Fig. 2. When the plunger has been depressedas far as possible the upper ends of the slots 27 abut the spindle 28and the shoulder on the outside of the plunger rests upon the top of themounting sleeve 24. Further depression of the plungerv is thereforeimpossible without damage to the switch.

However, due to inaccuracies in mounting the switch, or due to overthrowof the door or other object with which the plunger is cooperating, theremay bea tendency to move the plunger further than is necessary tooperate the switch. But, since the door presses against the button 36and not against the plunger, the button may be moved further, Y

compressing the auxiliary spring and taking up the overthrow and thereby.saving the switch from damage. The position 'of the parts when thisoverthrow is taken u is shown in Fig. 3. Upon movement of the oor awayfrom the button the parts assume the position of Fig. 1 by reason of thestrength of the main spring 38 being great enou h to raise the plungeragainst the bias o the switch spring.

The switch is particularly useful in con# nection with a door, and insuch a case would be mounted so that the closing of the door woulddepress the plunger and open the switch and opening of the door wouldrelease the plunger and allow the switch to be opened automaticallybythe pressure of the main spring causing the plunger to rise. However,the switch is in no wise limited to this use but may be varied ininnumerable ways to suit varieties of situations.

From the foregoing it will be seen that we have constructed' a compactswitch operating mechanism for use with a conventional type of snapswitch which will take up all overthrow which might normally occur dueto expansion and contraction of parts cooperating with the switch or dueto inaccuracy in mounting the switch.il Obviously the switch mechanismper se may be varied widely within the scope of the invention. Manychanges in form will occur to those skilled in the art', therefore we donot limit ourselves to the specific embodiment of the switch shownherein.

1. An electric switch comprising a casing, a sleeve mounted on saidcasing, a plunger Blidably engaged with said sleeve, a spindlejournalledin said sleeve and limiting the movement of said plunger, abutton in said plunger and movable relatively thereto, main andauxiliary springs in said plunger constantly urging said plunger andbutton in one direction, and switch mechanism engaged and operated bysaid plunger.

2. An electric switch comprising a casing, a sleeve mounted on saidcasing, a plunger slidably engaged with said sleeve, aspindle journalledin said sleeve, and limiting the movement of said plunger, a button insaid plunger and movable relatively thereto, main and auxiliary springsin said plunger constantly urging said plunger and button in onedirection, a switch lever mounted on said spindle, and switch mechanismactuated by said lever as said plunger is moved.

8. An electric switch comprising a casing, a sleeve mounted on saidcasing, a plunger slidably engaged with said sleeve, a spindle journalled in said sleeve and passing through a slot in said plunger tolimit the movement thereof, a button in said plunger and movablerelatively thereto, main and auxiliary springs in said plunger pressingagainst said button and constantly urging said plunger and button in onedirection, a switch lever mounted on said spindle, and switch mechanismactuated by said lever, as said plunger is moved.

In testimony whereof We have signed our names to this specification.

' HANS CHRISTIAN HANSEN.

ALFRED JOHN BENNETT.

